名词性从句:
1.最常见的连接词是that在宾语从句中的运用,如:I know that you will come. 句中的that 就是连接词,作用就是连接主句和从句,不充当成分也没有含义,只起风向标的作用,告诉你接下来的部分是一个整体,及that you will come 充当know 的宾语。
2.whether和if 也是引导名词性从句的连词,与that相同的地方是也不充当从句中的成分,但是是有含义的,"是否"。通常用于有疑问的句子,确定性。我们把that,whether, 和if 称为名词性从句连接词里的"3"。
3.名词性从句连接词里的"4":where, when, why, how。此时从句中主谓宾这种主要成分都是不缺少的,缺少的是状语部分,如:I want to go to Walmart, but I don't know_____ it is. 此时填where,缺少地点。
4.名词性从句连接词里的"5":what,who, whom, which, whose. 缺成分指物用what;缺成分指人用who。
5.如:______ doesn't does kill you makes you stronger. 填what 指事物。I don'tknow _____ took it away. 填who 指人。which 和 whose 后面通常还需接一个名词,如:I don't know which one I should buy. I don't know whose book it is.
6.变体部分:whatever,however等相当于no matter what,no matterhow,如:I will do _____ makes her happy. 填whatever。
定义从句:
引导词必须做从句中的句子成分
if条件语句,主将从现。主句是祈使句或者有情态动词时,使用一般现在时